We present results of cosmological N-body hydrodynamic chemistry simulations of primordial structure growth and evolution in a scenario with warm dark matter (WDM) having a mass of 3 keV (thermal relic) and compare with a model consisting of standard cold dark matter (CDM).We focus on the high-redshift universe (z > 6), where the structure formation process should better reflect the primordial (linear) differences in terms of matter power spectrum. We find that early epochs can be exceptional probes of the dark matter nature. Non-linear WDM power spectra and mass functions are up to 2 dex lower than in CDM and show spreads of factor of a few persisting in the whole first Gyr. Runaway molecular cooling in WDM haloes results severely inhibited because of the damping of power at large k modes and hence cosmic (Populations III and II-I) star formation rate (SFR) is usually suppressed with respect to CDM predictions. Luminous objects formed in a WDM background are very rare at z > 10, due to the sparser and retarded evolution of early WDM minihaloes during the dark ages and their lack can be fitted with a simple analytical formula depending only on magnitude and redshift. Future high-z observations of faint galaxies have the potential to discriminate between CDM and WDM scenarios by means of cosmic stellar mass density and specific SFR, as well. When compared to the effects of alternative cosmologies (e.g. non-Gaussian or dark energy models) or of high-order corrections at large z (e.g. primordial streaming motions or changes in the pristine initial mass function) the ones caused by WDM are definitely more dramatic. © 2014 The Authors.

The first billion years of a warm dark matter universe / Maio, U.; Viel, Matteo. - In: MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY. - ISSN 0035-8711. - 446:3(2015), pp. 2760-2775. [10.1093/mnras/stu2304]

The first billion years of a warm dark matter universe

Viel, Matteo
2015-01-01

Abstract

We present results of cosmological N-body hydrodynamic chemistry simulations of primordial structure growth and evolution in a scenario with warm dark matter (WDM) having a mass of 3 keV (thermal relic) and compare with a model consisting of standard cold dark matter (CDM).We focus on the high-redshift universe (z > 6), where the structure formation process should better reflect the primordial (linear) differences in terms of matter power spectrum. We find that early epochs can be exceptional probes of the dark matter nature. Non-linear WDM power spectra and mass functions are up to 2 dex lower than in CDM and show spreads of factor of a few persisting in the whole first Gyr. Runaway molecular cooling in WDM haloes results severely inhibited because of the damping of power at large k modes and hence cosmic (Populations III and II-I) star formation rate (SFR) is usually suppressed with respect to CDM predictions. Luminous objects formed in a WDM background are very rare at z > 10, due to the sparser and retarded evolution of early WDM minihaloes during the dark ages and their lack can be fitted with a simple analytical formula depending only on magnitude and redshift. Future high-z observations of faint galaxies have the potential to discriminate between CDM and WDM scenarios by means of cosmic stellar mass density and specific SFR, as well. When compared to the effects of alternative cosmologies (e.g. non-Gaussian or dark energy models) or of high-order corrections at large z (e.g. primordial streaming motions or changes in the pristine initial mass function) the ones caused by WDM are definitely more dramatic. © 2014 The Authors.
2015
446
3
2760
2775
https://doi.org/10.1093/mnras/stu2304
https://arxiv.org/abs/1409.6718
Maio, U.; Viel, Matteo
File in questo prodotto:
File Dimensione Formato  
stu2304.pdf

accesso aperto

Tipologia: Versione Editoriale (PDF)
Licenza: Non specificato
Dimensione 3.47 MB
Formato Adobe PDF
3.47 MB Adobe PDF Visualizza/Apri

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.11767/11761
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 40
  • ???jsp.display-item.citation.isi??? 39
social impact